As petroleum products become more expensive and difficult to obtain, and as polluting byproducts of petroleum combustion become more of a concern, there is greatly increased interest in engines that are more energy efficient and that are less polluting than petroleum based combustion engines. The combustion of hydrogen gas (H2) as a fuel with oxygen gas (O2) as the oxidant results in water (H2O) which is not at all polluting, and using ambient air as a source for the oxygen can be made to be minimally polluting if done in a way that minimizes the formation of potential pollutants such as nitrogen oxides.
Internal combustion engines using a liquid (fluid) to transfer the expansion force of exploding gases to a power takeoff have been known in various forms for many years. For example, U.S. Pat. No. 41,299 (Hugon; 1864) discloses a gas engine exploding a “gas source of hydrogen” mixed with air (as a source of oxygen). The explosion acts indirectly on a solid piston through an intermediate column of water.
U.S. Pat. No. 192,206 (Wertheim; 1877) discloses a U-shaped liquid piston “atmospheric gas engine”. A single explosion chamber is in a first closed leg of the U, and the second leg serves as a liquid reservoir open to atmospheric pressure. The bottom of the U is a paddle chamber having a paddle that oscillates within it in response to the oscillating movement of the liquid. The oscillating paddle is connected to a continuously rotating shaft through a mechanism to convert the oscillation to unidirectional rotation. Ignition of the gas is by means of a burner. Combustion gases are exhausted through “escape-valves” in the explosion chamber (last sentence of page 1). This patent is said to improve upon a previous patent U.S. Pat. No. 185,709 (Wertheim; 1876) which discloses a turbine valved to rotate in a single direction given oscillatory gas flows.
U.S. Pat. No. 706,366 (Vogt et al.; 1902) discloses an internal combustion motor having one or more cylinders and actuated by any kind of combustible (e.g., coal dust). A preferred embodiment has two cylinders (chambers 5, 6) filled with liquid and having explosions/compressions occurring alternately in the two chambers, thereby pushing back and forth a double-acting solid piston (2) in a cylinder (1) transversely oriented and opening on either side of the piston into a one of the chambers. The shaft (3) of the reciprocating piston is conventionally connected to a crankshaft and flywheel for power takeoff, and to a blower (4) for exhausting combustion gases. (See FIGS. 1 and 5.) There is also a governor (21). Similar engines are disclosed in U.S. Pat. No. 781,923 (Vogt; 1905), and U.S. Pat. No. 1,000,410 (Howell; 1911).
U.S. Pat. No. 1,085,865 (Humphrey; 1914) discloses a method of raising or forcing liquids wherein a reciprocating liquid, one movement or outstroke of it being due to the expansion of a combustible charge in one of a plurality of expansion chambers connected together, utilizing the kinetic energy of return stroke of the liquid to expel burnt products from one chamber and compress a fresh expansible charge in another chamber in the same cycle (claim 1 on page 5), and also to draw in a fresh charge. Using one-way valves on inlets and outlets, the liquid can be pumped.
U.S. Pat. No. 2,658,486 (De Waide; 1953) discloses an engine with a fluid piston interacting with a rotating displacement member (102) while guided by abutment members (104, 105, 121, 122, 125, 126) that seal against the displacement member and cause uni-directional flow of fluid that is oscillating between a pair of chambers (145, 146). The rotating displacement member (102) is cylindrical but mounted eccentrically on the drive shaft (101) conventionally connected to a flywheel (174). See especially FIGS. 1-4 and columns 8-9 of specification. The engine uses “conventional fuel injectors and fuel pumps”, and includes cooling of the liquid, liquid-tight seals on moving parts, and scavenging of exhaust gas/fluid.
U.S. Pat. No. 5,127,369 (Goldshtik; 1992) discloses an engine employing rotating liquid as a piston in order to overcome perceived problems with poor stability of the top surface of a flat liquid piston (Background, columns 1-2). Two or more daisy chained cylinders (201, 202) each with a unidirectional outlet tube passing through a hydromotor (205, 206 for power take-off) to an inlet tube of the next cylinder. The inlet and outlet tubes are tangential to the cylinder wall and cause the fluid piston to rotate in a circle around the cylinder wall at high speed and create a vortical liquid body (annulus) with a cylindrical cavity in the middle of the liquid. The cavity is the combustion chamber, and combustion pressure causes the inside diameter of the annulus to increase, thereby forcing liquid out of the outlet tube. The engine can use fuel injectors, diesel or otto cycle, and various fuels. The rotating liquid maintains cool cylinder walls.
U.S. Pat. No. 6,182,615 (Kershaw; 2001) discloses a combustion-driven hydroelectric generating system that has one or more combustion cylinders that contain a liquid and receive a combustible fuel/oxidizer mixture that is ignited and the explosive force pushes liquid into a gas-pressurized vessel, further pressurizing the gas to serve as a driving force for pressurized outlet flow of the liquid, which in turn can be used to operate a water wheel or hydroelectric generator or perform other work. To repeat a cycle, fluid must be pumped back into the combustion cylinder. The claimed embodiment has two combustion cylinders (12) alternately firing, and a two-chamber piston pump (45) for replenishing the fluid in the combustion cylinders. Liquid level sensors (26, 31) are used for control purposes.